Taylor-Dunn AMB Ambulance, Operation, T Roubleshooting And Replacement Parts Manual

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Motor Service
Motor Page 4
Insulation
Commutator
Incorrect
Hacksaw blade
Correct
Min. OD
Armature
Undercut
Typical burn mark on a shorted armature
2. Measure the diameter of the commutator.
• If the commutator is less than the minimum
diameter specified in section
Service Limits
,
then the motor must be replaced.
3. Measure the commutator undercut depth in 5-places
around the commutator.
• If any one of the measurements is less than the
minimum undercut depth specified in
Service
Limits
at the end of this section, then the
commutator must be undercut. Refer to
Repair
Commutator
section for information regarding
undercutting the commutator.
4. Inspect the commutator for groves.
• If the commutator is grooved then it must be
machined on a lathe. Do not machine the
commutator past the minimum diameter
specified in
Service Limits
section. Refer to
Repair Commutator
section for information
regarding machining the commutator.
5. Inspect the commutator for burn marks.
• Burn marks and/or raised commutator segments
90 or 180 degrees apart is evidence of a shorted
armature. A tool called a growler is required to
reliably test for a shorted armature.
6. Inspect the commutator for raised segments. Raised
segments could be a result of a stalled motor or
shorted armature. A tool called a growler is required
to reliably test for a shorted armature.
• If the armature is not shorted then the raised
segments can be removed by machining the
commutator. Do not machine the commutator
past the minimum diameter specified in
Service
Limits
section. Refer to
Repair Commutator
section for information regarding machining the
commutator.